Attachment of a hydrogen-bonding carboxylate side chain to an [FeFe]-hydrogenase model complex: Influence on the catalytic mechanism
2010 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 16, no 8, 2537-2546 p.Article in journal (Refereed) Published
Azapropanedithiolate (adt)-bridged model complexes of [FeFe]-hydrogenase bearing a carboxylic acid functionality have been designed with the aim of decreasing the potential for reduction of protons to hydrogen. Protonation of the bisphosphine complexes 4–6 has been studied by in situ IR and NMR spectroscopy, which revealed that protonation with triflic acid most likely takes place first at the N-bridge for complex 4 but at the FeFe bond for complexes 5 and 6. Using an excess of acid, the diprotonated species could also be observed, but none of the protonated species was sufficiently stable to be isolated in a pure state. Electrochemical studies have provided an insight into the catalytic mechanisms under strongly acidic conditions, and have also shown that complexes 3 and 6 are electro-active in aqueous solution even in the absence of acid, presumably due to hydrogen bonding. Hydrogen evolution, driven by visible light, has been observed for three-component systems consisting of [Ru(bpy)3]2+, complex 1, 2, or 3, and ascorbic acid in CH3CN/D2O solution by on-line mass spectrometry.
Place, publisher, year, edition, pages
Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA , 2010. Vol. 16, no 8, 2537-2546 p.
electrochemistry;electron transfer;enzyme model;iron-hydrogenase;proton reduction
IdentifiersURN: urn:nbn:se:su:diva-43569DOI: 10.1002/chem.200902278ISI: 000275685800026OAI: oai:DiVA.org:su-43569DiVA: diva2:358031